Civilians carrying bread and purchases are seen through a damaged bus at the Karaj al-Hajez crossing, a passageway separating Aleppo's Bustan al-Qasr, which is under the rebels' control and Al-Masharqa neighborhood, an area controlled by the regime, July 31.

Istanbul, Turkey — Among the journalists I know covering Syria, almost everyone is swearing off crossing the border and going inside the country. It’s not the threat of violence that’s stopping people, but the risk of kidnapping.

Working in Syria during the war has always been dangerous. Since March 2011, the conflict has claimed the lives of at least 24 journalists and 60 citizen journalists. But for those working inside, there were ways to limit exposure to violence and there was relative comfort in knowing that you could trust the people around you. In opposition-controlled areas, Syrians wanted the outside world to hear their story and many locals went to great lengths to protect and welcome foreign reporters.

Nearly two and a half years into the war, all of that has changed. In northern Syria, the country has fallen into economic ruin and hardcore jihadist groups, many with foreign ties, have proliferated. These two factors have created an environment ripe for kidnapping. Those desperate for cash are willing to abduct people for ransom or to sell them to extremist groups willing to pay for a foreign hostage.

Last Wednesday, armed men abducted Polish journalist Marcin Suder. According to media reports, militants took Mr. Suder from a media office in Idlib. An activist at the media center intervened in an attempt to stop the kidnappers, but he was beaten and hospitalized.

Even just several months ago, the abduction of a foreign reporter under these circumstances would have been unheard of, but kidnappings like Suder’s are rapidly undoing the idea that “safe houses” can exist in a place like Syria.

While some of the kidnappings appear to be conducted by criminal groups looking to make money, there are indications that groups with links to Al Qaeda or other extremist groups are now looking to kidnap people for potentially much more complex, political reasons. If this trend develops, it will drastically reduce the risk of foreigners surviving a kidnapping.

Already, Syrians throughout the north are suffering a rash of kidnappings. During my last visit there in late April and early May, I met one man who knew of eight people on his block who’d been kidnapped in recent months and he’d personally witnessed four of the abductions.

According to Reporters Without Borders, at least 15 foreign journalists have been kidnapped or gone missing inside Syria since the conflict began.

That figure likely does not include a number of incidents, like one that happened to me last November. Several other reporters and I were driving through an area of Aleppo that was firmly under opposition control when a car cut us off, gunmen surrounded our car, took our driver, and brought us back to their base for several hours. Eventually, they released us, claiming to have rescued us from another kidnapping attempt. They would not tell us who they were, what rebel group they belonged to, or even if they were Syrians.

I’ve heard a number of stories about reporters who experienced brief abductions like mine, but who were released within several hours. The kidnappings now taking place appear to be of a much more serious and dangerous nature. With at least 1,200 different opposition factions, controlling the various groups, or simply understanding who is a legitimate rebel military group or a criminal group will become exceedingly difficult.

Even those who travel to northern Syria without experiencing any close calls, often leave saying they’re unwilling to return because they feel unsafe due to the massive number of foreign fighters and jihadists.

More than making it difficult, if not impossible for journalists to deliver on-the-ground reporting on one of the most brutal wars in decades, the cause of the problem is one that can only spell a dark and troubled future for Syria.